Removal of diclofenac from contaminated water using polypyrrole: A comprehensive adsorption study

Abstract Polypyrrole (PPy) was synthesized via chemical oxidative polymerization using FeCl₃ as the oxidizing agent and evaluated as an adsorbent for removing diclofenac (DCF) from aqueous solutions. Unlike most studies focused on PPy composites, this study highlights the performance of pure, unmodified PPy, filling an important gap in the literature. The material exhibited a nodular, macroporous structure with a low specific surface area (9.017 m 2 g −1 ), and highly energetic adsorption sites. Adsorption studies showed that optimal DCF removal (97%) was achieved with low adsorbent dosages and adsorption capacity was influenced by pH, reaching a maximum at neutral conditions. Kinetic analysis revealed rapid adsorption, occurring primarily on the material's surface, while equilibrium data indicated an exothermic process with a maximum adsorption capacity of 305 mg g −1 . Desorption tests showed reversible adsorption, with ethanol being the most effective eluent. Physical interactions, such as hydrogen bonding, hydrophobic, and π–π interactions mainly drove adsorption mechanisms. Despite its low specific area, PPy demonstrated excellent DCF removal performance under mild operating conditions, making it a promising material for large‐scale water treatment applications, instilling hope for a more sustainable future.